From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 344CDC33C8C for ; Mon, 6 Jan 2020 19:06:55 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F0FFC2072E for ; Mon, 6 Jan 2020 19:06:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WZCso5AU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0FFC2072E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58406 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ioXiG-0005iY-LN for qemu-devel@archiver.kernel.org; Mon, 06 Jan 2020 14:06:52 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54478) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ioXWQ-0006TG-UG for qemu-devel@nongnu.org; Mon, 06 Jan 2020 13:54:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ioXWP-0001Rg-3K for qemu-devel@nongnu.org; Mon, 06 Jan 2020 13:54:38 -0500 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:54622 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ioXWO-0001R3-VP for qemu-devel@nongnu.org; Mon, 06 Jan 2020 13:54:37 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578336876; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NC4EGocwZpRI2+e3qyo8g2Pu/CERqWRnwIerHFqVqEg=; b=WZCso5AUw/mtK4ImxaYfLD7sGVaF61qg6XoNXTx4rYjATJp7CLjrXjehIRokf7JE3QE8ry NKExvunjZEQ49uTSja8SPUHBDNDwzpCL8viw3yeyMcBjuS3ZfFUeZXdsn5+ty3brRnuaI4 xcyGqNeHBc/tDia3OIW9S3siH6KwOV0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-nmIGWrOmPe6G7raILjx99g-1; Mon, 06 Jan 2020 13:54:34 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4C0D88EB6C1 for ; Mon, 6 Jan 2020 18:54:33 +0000 (UTC) Received: from work-vm (ovpn-117-53.ams2.redhat.com [10.36.117.53]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9B1B7272A3; Mon, 6 Jan 2020 18:54:25 +0000 (UTC) Date: Mon, 6 Jan 2020 18:54:22 +0000 From: "Dr. David Alan Gilbert" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [PATCH 050/104] virtiofsd: add seccomp whitelist Message-ID: <20200106185422.GM2798@work-vm> References: <20191212163904.159893-1-dgilbert@redhat.com> <20191212163904.159893-51-dgilbert@redhat.com> <20200106145618.GP2930416@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200106145618.GP2930416@redhat.com> User-Agent: Mutt/1.13.0 (2019-11-30) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: nmIGWrOmPe6G7raILjx99g-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Daniel P. Berrang=E9 (berrange@redhat.com) wrote: > On Thu, Dec 12, 2019 at 04:38:10PM +0000, Dr. David Alan Gilbert (git) wr= ote: > > From: Stefan Hajnoczi > >=20 > > Only allow system calls that are needed by virtiofsd. All other system > > calls cause SIGSYS to be directed at the thread and the process will > > coredump. > >=20 > > Restricting system calls reduces the kernel attack surface and limits > > what the process can do when compromised. > >=20 > > Signed-off-by: Stefan Hajnoczi > > with additional entries by: > > Signed-off-by: Ganesh Maharaj Mahalingam > > Signed-off-by: Masayoshi Mizuma > > Signed-off-by: Misono Tomohiro > > Signed-off-by: piaojun > > Signed-off-by: Vivek Goyal > > Signed-off-by: Eric Ren > > --- > > Makefile | 2 + > > tools/virtiofsd/Makefile.objs | 5 +- > > tools/virtiofsd/passthrough_ll.c | 2 + > > tools/virtiofsd/seccomp.c | 141 +++++++++++++++++++++++++++++++ > > tools/virtiofsd/seccomp.h | 14 +++ > > 5 files changed, 163 insertions(+), 1 deletion(-) > > create mode 100644 tools/virtiofsd/seccomp.c > > create mode 100644 tools/virtiofsd/seccomp.h > >=20 > > diff --git a/Makefile b/Makefile > > index 8a5746d8a0..3f5d04e1f7 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -322,8 +322,10 @@ HELPERS-y =3D > > HELPERS-$(call land,$(CONFIG_SOFTMMU),$(CONFIG_LINUX)) =3D qemu-bridge= -helper$(EXESUF) > > =20 > > ifdef CONFIG_LINUX > > +ifdef CONFIG_SECCOMP > > HELPERS-y +=3D virtiofsd$(EXESUF) > > vhost-user-json-y +=3D tools/virtiofsd/50-qemu-virtiofsd.json > > +endif > > =20 > > ifdef CONFIG_VIRGL > > ifdef CONFIG_GBM > > diff --git a/tools/virtiofsd/Makefile.objs b/tools/virtiofsd/Makefile.o= bjs > > index 67be16332c..941b19f18e 100644 > > --- a/tools/virtiofsd/Makefile.objs > > +++ b/tools/virtiofsd/Makefile.objs > > @@ -6,5 +6,8 @@ virtiofsd-obj-y =3D buffer.o \ > > fuse_signals.o \ > > fuse_virtio.o \ > > helper.o \ > > - passthrough_ll.o > > + passthrough_ll.o \ > > + seccomp.o > > =20 > > +seccomp.o-cflags :=3D $(SECCOMP_CFLAGS) > > +seccomp.o-libs :=3D $(SECCOMP_LIBS) > > diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthr= ough_ll.c > > index 754ef2618b..701608c6df 100644 > > --- a/tools/virtiofsd/passthrough_ll.c > > +++ b/tools/virtiofsd/passthrough_ll.c > > @@ -58,6 +58,7 @@ > > #include > > =20 > > #include "passthrough_helpers.h" > > +#include "seccomp.h" > > =20 > > #define HAVE_POSIX_FALLOCATE 1 > > struct lo_map_elem { > > @@ -2073,6 +2074,7 @@ static void setup_sandbox(struct lo_data *lo, str= uct fuse_session *se) > > { > > setup_namespaces(lo, se); > > setup_mounts(lo->source); > > + setup_seccomp(); > > } > > =20 > > int main(int argc, char *argv[]) > > diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c > > new file mode 100644 > > index 0000000000..6359bb55bb > > --- /dev/null > > +++ b/tools/virtiofsd/seccomp.c > > @@ -0,0 +1,141 @@ > > +/* > > + * Seccomp sandboxing for virtiofsd > > + * > > + * Copyright (C) 2019 Red Hat, Inc. > > + * > > + * SPDX-License-Identifier: GPL-2.0-or-later > > + */ > > + > > +#include "seccomp.h" > > +#include "fuse_i.h" > > +#include "fuse_log.h" > > +#include > > +#include > > +#include > > +#include > > + > > +/* Bodge for libseccomp 2.4.2 which broke ppoll */ > > +#if !defined(__SNR_ppoll) && defined(__SNR_brk) > > +#ifdef __NR_ppoll > > +#define __SNR_ppoll __NR_ppoll > > +#else > > +#define __SNR_ppoll __PNR_ppoll > > +#endif > > +#endif > > + > > +static const int syscall_whitelist[] =3D { > > + /* TODO ireg sem*() syscalls */ > > + SCMP_SYS(brk), > > + SCMP_SYS(capget), /* For CAP_FSETID */ > > + SCMP_SYS(capset), > > + SCMP_SYS(clock_gettime), > > + SCMP_SYS(clone), >=20 > clone2 ? clone3 ? IIC some archs in Linux > will require the newer variants. It looks like clone2 was an Itanium only thing; lets ignore that. Clone3 is very new; so we're going to have to do: #ifdef __NR_clone3 SCMP_SYS(clone3); #endif > > + SCMP_SYS(close), > > + SCMP_SYS(copy_file_range), > > + SCMP_SYS(dup), > > + SCMP_SYS(eventfd2), > > + SCMP_SYS(exit), > > + SCMP_SYS(exit_group), > > + SCMP_SYS(fallocate), > > + SCMP_SYS(fchmodat), > > + SCMP_SYS(fchownat), > > + SCMP_SYS(fcntl), > > + SCMP_SYS(fdatasync), > > + SCMP_SYS(fgetxattr), > > + SCMP_SYS(flistxattr), > > + SCMP_SYS(flock), > > + SCMP_SYS(fremovexattr), > > + SCMP_SYS(fsetxattr), > > + SCMP_SYS(fstat), > > + SCMP_SYS(fstatfs), > > + SCMP_SYS(fsync), > > + SCMP_SYS(ftruncate), > > + SCMP_SYS(futex), > > + SCMP_SYS(getdents), > > + SCMP_SYS(getdents64), > > + SCMP_SYS(getegid), > > + SCMP_SYS(geteuid), > > + SCMP_SYS(getpid), > > + SCMP_SYS(gettid), > > + SCMP_SYS(gettimeofday), > > + SCMP_SYS(linkat), > > + SCMP_SYS(lseek), > > + SCMP_SYS(madvise), > > + SCMP_SYS(mkdirat), > > + SCMP_SYS(mknodat), > > + SCMP_SYS(mmap), > > + SCMP_SYS(mprotect), > > + SCMP_SYS(mremap), > > + SCMP_SYS(munmap), > > + SCMP_SYS(newfstatat), > > + SCMP_SYS(open), > > + SCMP_SYS(openat), > > + SCMP_SYS(ppoll), > > + SCMP_SYS(prctl), /* TODO restrict to just PR_SET_NAME? */ > > + SCMP_SYS(preadv), > > + SCMP_SYS(pread64), > > + SCMP_SYS(pwritev), > > + SCMP_SYS(pwrite64), > > + SCMP_SYS(read), > > + SCMP_SYS(readlinkat), > > + SCMP_SYS(recvmsg), > > + SCMP_SYS(renameat), > > + SCMP_SYS(renameat2), > > + SCMP_SYS(rt_sigaction), > > + SCMP_SYS(rt_sigprocmask), > > + SCMP_SYS(rt_sigreturn), > > + SCMP_SYS(sendmsg), > > + SCMP_SYS(setresgid), >=20 > Should be setresgid32 instead I think. We don't > want the legacy syscall that's limted to 16-bit GIDs >=20 > Needs the code fix I mention in an earlier patch too. >=20 > > + SCMP_SYS(setresuid), >=20 > Same as above OK. Interestingly I see setresuid/setresgid blacklisted as SET_PRIVILEGED in qemu's qemu-secomp.c but not the 32 versions; perhaps those should be added - but then I don't understand why qemu would ever allow them to be enabled. Dave > > + SCMP_SYS(set_robust_list), > > + SCMP_SYS(symlinkat), > > + SCMP_SYS(time), /* Rarely needed, except on static builds */ > > + SCMP_SYS(tgkill), > > + SCMP_SYS(unlinkat), > > + SCMP_SYS(utimensat), > > + SCMP_SYS(write), > > + SCMP_SYS(writev), > > +}; >=20 >=20 > Regards, > Daniel > --=20 > |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| > |: https://libvirt.org -o- https://fstop138.berrange.c= om :| > |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK